West Nile Virus and Other Mosquito-Borne Disease National Surveillance Report - July 27 to August 2, 2014 (Report Week 31)

Summary

Humans: As of surveillance week 31 (July 27 to August 2, 2014), no confirmed human cases of West Nile virus (WNV) have been reported to the Public Health Agency of Canada (the Agency).

Mosquitoes: Since the start of the 2014 West Nile Virus (WNV) season, 21 mosquito pools tested positive for WNV in Canada: nine in Quebec [Montreal (8) and Laval (1)]; five in Ontario [Lambton Health Unit (1), Peel Region (1), Halton Region (1) and Middlesex-London (2)] and seven in Manitoba [Interlake-Eastern Health Region (4), Winnipeg Health Region (1) and Southern Health Region (2)].

Dead Birds: Since the start of the 2014 WNV season, the Canadian Wildlife Health Cooperative has tested 34 dead birds for WNV in Canada: Saskatchewan (21), Ontario (10) and Quebec (3). No dead birds positive for WNV have been reported.

During surveillance week 31, the Canadian Wildlife Health Cooperative tested three dead birds for WNV in Canada: Saskatchewan (3). No dead birds positive for WNV have been reported.

Domestic Animals: No animals positive for WNV have been reported by the Canadian Food Inspection Agency.

United States

Since the start of the 2014 West Nile Virus (WNV) season, 82 human WNV cases [Arizona (13), Arkansas (1), California (19), Colorado (5), District of Columbia (1), Georgia (1), Iowa (3), Louisiana (11), Mississippi (5), Missouri (2), Nebraska (5), New York (1), Oklahoma (1), South Dakota (12), Tennessee (1), Texas (1) and Wisconsin (1)] have been reported by the Centers for Disease Control and Prevention. Of these, 39 (47.5%) were diagnosed as neuroinvasive disease cases and 43 (52.4%) as non-neuroinvasive cases. Four fatal cases were reported. Twenty-eight presumptive viremic blood donors have been identified.

European Union, European Economic Area and Neighbouring Countries

Since the start of the 2014 West Nile Virus (WNV) season, no human cases have been reported in the European Union/European Economic Area by the European Centre for Disease Prevention and Control. Twenty-five human cases have been reported in neighbouring countries: Bosnia and Herzegovina (13), Russian Federation (7) and Serbia (5).

Figure 1: West Nile Virus clinical cases and asymptomatic Infections, by Province/Territory and by report week, 2014 season

* Episode date could include one of the following: onset date, diagnosis date, lab sample date, or reporting date.

Table 1: West Nile Virus clinical cases and asymptomatic infections, by Province/Territory and by report week, 2014 seasonFootnote *
Provinces and
Territories
Report Week of 2014
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
Newfoundland and Labrador 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Prince Edward Island 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
New Brunswick 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Nova Scotia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Alberta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
British Columbia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Yukon Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Northwest Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Nunavut 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Total 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Table 2: West Nile Virus human clinical cases and asymptomatic infections by Province/Territory for the current report week and year to date, 2014 season
Provinces and Territories Week 31: July 27 to August 2, 2014
West Nile virus Neurological syndrome West Nile virus Non-Neurological syndrome Unclassified/
Unspecified
Total clinical
casesFootnote 1
Number of travel-related casesFootnote 2 West Nile virus
asymptomatic infectionsFootnote 3
Newfoundland and Labrador 0 0 0 0 0 0
Prince Edward Island 0 0 0 0 0 0
Nova Scotia 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0
Quebec 0 0 0 0 0 0
Ontario 0 0 0 0 0 0
Manitoba 0 0 0 0 0 0
Saskatchewan 0 0 0 0 0 0
Alberta 0 0 0 0 0 0
British Columbia 0 0 0 0 0 0
Yukon Territory 0 0 0 0 0 0
Northwest Territory 0 0 0 0 0 0
Nunavut 0 0 0 0 0 0
Total 0 0 0 0 0 0
  Year to date: January 1 to August 2, 2014
Newfoundland and Labrador 0 0 0 0 0 0
Prince Edward Island 0 0 0 0 0 0
Nova Scotia 0 0 0 0 0 0
New Brunswick 0 0 0 0 0 0
Quebec 0 0 0 0 0 0
Ontario 0 0 0 0 0 0
Manitoba 0 0 0 0 0 0
Saskatchewan 0 0 0 0 0 0
Alberta 0 0 0 0 0 0
British Columbia 0 0 0 0 0 0
Yukon Territory 0 0 0 0 0 0
Northwest Territory 0 0 0 0 0 0
Nunavut 0 0 0 0 0 0
Total 0 0 0 0 0 0

Figure 2: West Nile Virus clinical cases and asymptomatic infections by report week for selected years

* Episode date could include one of the following: onset date, diagnosis date, lab sample date, or reporting date.

Table 3: West Nile Virus clinical cases and asymptomatic infections by report week for selected years
Years Report Week of 2014
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
2013 1 0 0 0 0 1 1 0 0 0 1 2 1 5 5 8 17 11 13 13 11 9 1 6 1 0 4 1 0 1 0
2012 1 0 0 0 0 0 0 0 0 0 3 5 11 16 27 53 63 57 43 43 45 24 30 14 9 5 1 0 0 0 0
2007 0 0 0 0 0 0 2 2 3 4 11 35 36 72 139 424 471 443 287 182 116 71 30 18 10 11 5 4 2 0 0
2005 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 4 11 28 28 38 45 27 15 7 12 3 3 1 0 0 0
2003 0 0 0 0 0 0 0 0 0 1 1 1 5 11 9 27 66 249 323 324 178 107 82 37 14 8 4 3 0 0 0
Table 4.1: Reported cumulative number of West Nile Virus positive mosquito pools by Province/Territory and by report week, 2014 seasonFootnote *
Provinces and
Territories
Report week of 2014
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
Newfoundland and Labrador 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Prince Edward Island 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
New Brunswick 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Nova Scotia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 1 4 9                                
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 2 5                                
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7                                
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Alberta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
British Columbia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Yukon Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Northwest Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Nunavut 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Total 0 0 0 0 0 0 0 0 0 0 0 0 1 6 21                                
Table 4.2: Detailed mosquito pools tested and positive mosquito pools by Province/Territory, 2014 season
Provinces and
Territories
Year to date: January 1 to August 2, 2014
Number of mosquito
pools tested
Number of positive
mosquito pools
Percentage of positive
mosquito pools (%)
Newfoundland and Labrador 0 0 0
Prince Edward Island 0 0 0
New Brunswick 0 0 0
Nova Scotia 0 0 0
Quebec 5,743 9 0.2
Ontario 2,061 5 0.2
Manitoba 734 7 1.0
Saskatchewan 273 0 0
Alberta 0 0 0
British Columbia 101 0 0
Yukon Territory 0 0 0
Northwest Territory 0 0 0
Nunavut 0 0 0
Total 8,912 21 0.2

Figure 3: Reported number of dead birds testing positive for West Nile Virus by Province/Territory and by report week, 2014 seasonFigure 3 - Footnote *

Table 5: Reported number of dead birds testing positive for West Nile Virus by Province/Territory and by report week, 2014 seasonFootnote *
Provinces and
Territories
Report weeks of 2014
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 Total
Newfoundland and Labrador 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Prince Edward Island 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
New Brunswick 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Nova Scotia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Quebec 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Ontario 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Manitoba 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Saskatchewan 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Alberta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
British Columbia 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Yukon Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Northwest Territory 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Nunavut 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0
Total 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                 0

Figure 4: Percentage of dead birds testing positive for West Nile Virus in the 2014 season by report week, as compared to the 2003, 2012 and 2013 seasons

Table 6: Percentage of dead birds testing positive for West Nile Virus in the 2014 season by report week, as compared to the 2003, 2012 and 2013 seasons
  Report Week of 2014
17 18 19 20 21 22 23 24 26 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
Numbers positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Numbers tested 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 34 3                                
Percentage positive 2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0                                
Numbers positive 2013 0 0 0 0 0 0 0 0 0 1 0 0 5 2 13 9 6 6 18 9 6 6 2 0 1 0 0 0 0 0 0
Numbers tested 2013 0 0 0 1 0 0 0 2 2 6 8 5 9 10 29 19 16 16 24 13 9 10 3 3 2 0 0 0 0 0 0
Percentage positive 2013 0 0 0 0 0 0 0 0 0 20 0 0 56 20 45 47 38 38 75 69 67 60 67 0 50 0 0 0 0 0 0
Percentage positive 2012 0 0 0 0 0 0 0 0 0 0 33 67 33 67 33 50 67 64 67 33 67 67 55 0 0 0 0 0 0 0 0
Percentage positive 2003 0 0 1 0 1 1 1 1 1 3 3 6 7 10 17 21 38 35 43 46 45 45 58 29 20 15 8 0 0 0 0
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